1. Field of the Invention
The present invention relates to a one-way clutch of package type-which is used in general industrial fields for application to over-run, index or back stop and in which an outer race, an inner race and bearings are incorporated integrally with each other.
2. Related Background Art
A one-way clutch has widely been used in general industrial fields. For example, the one-way clutch is used in over-run (in which the clutch is engaged or idly rotated by utilizing a difference in rotation between an outer race and an inner race), various automatic machines, fans, pumps, index (used in intermittent feed-mechanisms for converting a continuous rotation or a reciprocal movement of an input shaft into an intermittent movement) printing machines, wrapping machines and press machines, and back stop for conveyors. Further, the one-way clutch is used in automatic transmissions of vehicles and torque converters.
For these applications, a one-way clutch of package type in which a one-way clutch comprising a splug having a wedging function or a torque transferring member such as a clutch having a one-way clutch function is supported at its both sides by radial bearings and is combined integrally by an outer race, an inner race and snap rings has been used. For example, such a one-way clutch of package type is disclosed in Japanese Patent Application Laid-open No. 2002-310200 (corresponding to U.S. Pat. No. 6,679,364).
In case of such a one-way clutch of package type, an inner one-way clutch member is designed so as not to cause axial restraint to permit a one-way clutch action. Further, in order to integrate the one-way clutch member, outer race and inner race, steps are formed between the outer race and the inner race and ball bearings are provided at both sides and an axial movement is regulated by snap rings.
However, due to dispersion in a dimension of the step of the outer or inner race, dispersion in a distance between the step of the outer race and the snap ring, dispersion in a width of a groove for the snap ring, dispersion in a width of the snap ring, dispersion in a width of the bearing and/or dispersion in bearing clearance, when the outer race and the inner race are combined, great axial play is generated.
When the one-way clutch of package type is used in an automatic assembling machine, a printing machine or a press machine, which requires high accuracy, such axial play may affect a bad influence upon such a machine. Particularly, in an apparatus which includes a vertical reciprocating mechanism and in which the one-way clutch is used on a vertical axis, the axial play must be reduced as much as possible in order to maintain positional accuracy.